Hmmm...can you give us some more info? Is this what you are talking about? Cardiology Specialty | Duke School of Nursing
That looks like just 9 hours of credit:
The cardiovascular specialty offers students the opportunity to become expert clinicians in the care of individuals with cardiovascular disease. The online coursework includes content from the American College of Cardiology Core Curriculum and incorporates the latest evidence based knowledge in the field. On-campus intensives provide students opportunities to engage with cardiovascular clinicians and inquire about novel research and innovative practice. As a synthesis, the student participates in clinical practice under the mentorship of an expert clinician in a cardiovascular specialty.
NUR 801: Advanced Practice Nursing: Cardiovascular Specialty I (Fall only)
NUR 802: Advanced Practice Nursing: Cardiovascular Specialty II (Spring only)
NUR 805: Advanced Practice Nursing in Adult-Gerontology Cardiovascular Synthesis
Loooks like it includes 224 hours of clinical.